Table 2:

Autonomic function characteristics during supine and last 5 minutes of graded head up tilt (HUT), hyperventilation, handgrip, Valsalva maneuver, and deep breathing in patients with postural tachycardia syndrome (POTS, N=12) and healthy control (N=10).

Parameter	POTS		Control
	Supine	HUT	Supine	HUT
Tilt Table Test
HR, bpm	78±3	122±5*	66±3	85±3
Systolic BP, mmHg	103±2	107±3	107±2.5	110±2.5
Diastolic BP, mmHg	66±1.5	71±3	69±2.5	73±2
iMSNA, burst/min	12±1.5*	38±3	20±2	42±5
iMSNA, burst/100b	14.3±2*	29±3	31±3	41±4
iMSNA, burst/100b	2.5±0.4*	12.5±2.5	5±0.5	12±2
Norepinephrine, pg/ml	164±14	503±55	209±32	480±50
DHPG / NE ratio	7.5±1	3.3±0.4	6.9±0.6	3.4±0.3
Epinephrine, pg/ml	22±3	80±10	14±3	110±20
Autonomic Function Test Sympathetic Response
Δ BP Hyperventilation, mmHg	−8±3		−9±3
Δ BP Hand Grip, mmHg	12±2.5		7.5±1.5
Δ BP Cold Pressor Test, mmHg	20±4		17±5
Δ BP Valsalva Phase 2, mmHg	−32±5.8*		−14±4
Δ BP Valsalva Phase 4, mmHg	32±3		25±5
Vagal Response
Deep Breathing RSA Ratio	1.3±0.01*		1.6±0.05
Valsalva Ratio	2.0±0.1		1.9±0.1

HR, Heart Rate, BP, Blood Pressure, iMSNA, Integrated Muscle Sympathetic Activity, DHPG, Dihydroxyphenylglycol, NE, Norepinephrine, RSA, Respiratory Sinus Arrhythmia

^*significant group differences between POTS and controls, p<0.05